Wooden materials are used for floorings and cabinets in business class and customized aircrafts. These wood materials are often coated to achieve a highly glossy, luxurious appearance. The best known method of achieving a high gloss appearance is to apply a polyurethane sealer coat to the wood substrate followed by 3 to 4 coats of polyester topcoat.
Wooden materials used for aircraft interiors must meet demanding property profiles with specifications issued by aircraft manufacturers and regulatory authorities. Particularly, the required property profile includes the visual aspect stability of the wooden substrate. Visual aspect stability is the ability of a substance or part to resist shrinkage and/or expansion. When subjected to varying degrees of temperature, moisture, pressure, or other stress, wood products coated by conventional methods do not sustain the resistance of shrinkage and/or expansion and require laborious and costly rework within as few as two months of use.
Low visual aspect stability is caused by wood cells absorbing or releasing moisture, affecting the surface finishes of the wood products. Low visual aspect stability is particularly common in wood veneers. Veneers are typically three layers of 1 to 3 millimeter of thick wood attached together, with the front layer being the decorative face. Veneers can provide the appearance of a solid wood product while greatly reducing the weight. Visual aspect stability decreases when the veneered product shrinks or expands due to external humidity or temperature changes, or more slowly under a constant humidity and temperature over a period, especially when the veneer surface layer has no underlying layers or core.
Some of the causes of the decrease of the visual aspect stability are mentioned in C. L. Forbes, Understanding and Minimizing Veneer Checking on Furniture Panels (1997), available at http://www.ces.ncsu.edu/nreos/wood/wpn/venchk.htm. Conventional measures of coating, however, do not enhance the wooden article's visual aspect stability. The present inventors have found that coating the wooden surface with conventional polymers while provides the surface with a glossy appearance, does not provide visual aspect stability even under regular weather conditions for as few as two months.
Therefore, there is a demand for improved methods in providing resistant wood or veneer finish with superior visual aspect stability to protect wooden substrates against variable temperature conditions anticipated by standard aviation complications.